A braking system typically includes a master cylinder which is fluidly coupled to downstream braking circuits. During an initial period of actuation, the master cylinder generates fluid pressure in downstream braking circuits and displaces fluid in order to place friction members of the braking system, e.g., brake pads, against complementary surfaces, e.g., a rotor or a drum. In certain circumstances, brake pads may be displaced away from the rotor, thereby generating a gap between the brake pads and the rotor. When fully actuated, the brake pads are in contact with the rotor, and thereafter the brake pads perform the desired braking function. When actuation is first initiated, however, the brake pads are not in physical contact with the rotor. This lack of physical contact results in minimal pressure buildup in the downstream braking circuits, which results in lack of braking. In addition to the lack of braking, an operator of the vehicle may receive a different pedal feedback when the actuation is first initiated as compared to the pedal feedback the operator receives once the brake pads are in contact with the rotor. This difference in the pedal feedback can be unsettling to the operator.
One way to shorten the lack of braking and reduce the unsettling difference in the pedal feedback when the actuation is first initiated is to include a check valve, which allows a fast refill of the downstream braking circuits from a reservoir followed by isolating the braking circuits from the reservoir. The check valve, however, adds cost and may be unreliable in a harsh environment associated with typical braking systems.
Therefore, it is highly desirable to provide a master cylinder construction which can minimize the lack of braking and reduce the unsettling difference in the pedal feedback when the actuation is first initiated by rapidly increasing pressure in the downstream braking circuits.